I have not yet been to the track, but have done some autocrossing with rather quick setups (65-30ish mph braking in 2 places) and have been working on trail braking more aggressively. I have not felt anything like what you describe. I am on stock pads. Could it have to do with the amount of forward g's you are getting, not only the lateral g's?

Yes, I was simply answering the question about how the car senses it is cornering.

In addition to the sensors that I referred to, the actuation of CBC is also dependent vehicle speed, the relative rates of rotation of the left and right front wheels, and brake pedal pressure.

Having just spent 3 days at VIR, I'm once again obsessing about how to eliminate the dreadful Corner Braking Control (CBC) function.

Anyone have insight into feasability of replacing the existing ABS Pump controller with one from an E9x M3?

Since the programming is in the controller, this might allow the CBC to be turned off as it is on the E9x M3.

Of course, as must be done whenever this device is replaced, there would need to be some coding to the ecu and, possibly, valve and sensor calibration.

Thoughts/opinions appreciated!

Neil

I think this could be a fruitful direction, but before changing the controller, why not compare .TRC coding files of the 1M and M3 to see which settings differ (=tedious job). Next select some sensible CBC related candidate parameters (based on their names, however the parameter names can be very function unrelated unfortunately) and try 1 by 1 to code the 1M with the M3 value, ....

"I'll also check with the boys down at the crime lab, I heard they've got 4 more detectives on the case, they got them working in shifts now". (= silly movie reference) Actually I posted a query on the coding forum to find out if someone knows the CBC related coding parameter, but so far no response. I'm also checking with another source. Hope we can get you sorted.

I think this could be a fruitful direction, but before changing the controller, why not compare .TRC coding files of the 1M and M3 to see which settings differ (=tedious job). Next select some sensible CBC related candidate parameters (based on their names, however the parameter names can be very function unrelated unfortunately) and try 1 by 1 to code the 1M with the M3 value, ....

"I'll also check with the boys down at the crime lab, I heard they've got 4 more detectives on the case, they got them working in shifts now". (= silly movie reference) Actually I posted a query on the coding forum to find out if someone knows the CBC related coding parameter, but so far no response. I'm also checking with another source. Hope we can get you sorted.

It'd be great if you could find out whether we could "simply" re-code the ABS control module. I've looked into it some, but couldn't find anyone that was either able or willing to do it.

Neil's description of what's happening is exactly what I feel in the same kinds of situations. I've got about 1,200 track miles on my 1M so far this year. All of it has been at Road America or Blackhawk. I'm also using PFC-01 pads, Motul 600 and steel brake lines. One difference is that I am using either Grand-AM take off slicks or Hooiser slicks. I've also described the felling as a short hesitation as I trying to rotate the car.

At the ALMS race at Road America I got a pit tour and after the tour I got a chance to talk to someone from the product group at BMW NA. I told him I really liked my 1M except for the corner brake control still being on when DSC is completely "off". He was somewhat surprised that it was still coming on. He thought 1Ms were the same as E9x M3s and he thought it was off when DSC was off for an M3.

I offered to send him the traces from my AIM Solo DL that show opposite corner brake pad pressure when there is no pressure on the brake pedal. I didn't think he was interested in getting them.

I also told him that it would be really nice if the push to pass function was actually controllable and predictable. On this one he agreed. I told him it would be nice if it was a button instead of being activated with the gas pedal.

Neil's description of what's happening is exactly what I feel in the same kinds of situations. I've got about 1,200 track miles on my 1M so far this year. All of it has been at Road America or Blackhawk. I'm also using PFC-01 pads, Motul 600 and steel brake lines. One difference is that I am using either Grand-AM take off slicks or Hooiser slicks. I've also described the felling as a short hesitation as I trying to rotate the car.

At the ALMS race at Road America I got a pit tour and after the tour I got a chance to talk to someone from the product group at BMW NA. I told him I really liked my 1M except for the corner brake control still being on when DSC is completely "off". He was somewhat surprised that it was still coming on. He thought 1Ms were the same as E9x M3s and he thought it was off when DSC was off for an M3.

I offered to send him the traces from my AIM Solo DL that show opposite corner brake pad pressure when there is no pressure on the brake pedal. I didn't think he was interested in getting them.

I also told him that it would be really nice if the push to pass function was actually controllable and predictable. On this one he agreed. I told him it would be nice if it was a button instead of being activated with the gas pedal.

Yeah, I've discussed it with several of the instructors at the M Performance Driving school in Spartanburg and, despite their having driven lots of 1Ms, they all "claim" to have no idea what I'm talking about.

It'd be great if you could find out whether we could "simply" re-code the ABS control module. I've looked into it some, but couldn't find anyone that was either able or willing to do it.

Really appreciate your help!

Neil

baby steps, baby steps:

Meanwhile I'm up and running with coding, and discovered that our 1M has a seemingly 1M dedicated DSC module, that is listed as M1DSC in the module list. The strange thing was that I got an error notification when trying to read out the M1DSC module parameters. Those parameters should be in my all modules parameter file, I'm hoping that changing one or a couple of these parameters could change or disable the CBC function.

Meanwhile I'm up and running with coding, and discovered that our 1M has a seemingly 1M dedicated DSC module, that is listed as M1DSC in the module list. The strange thing was that I got an error notification when trying to read out the M1DSC module parameters. Those parameters should be in my all modules parameter file, I'm hoping that changing one or a couple of these parameters could change or disable the CBC function.

I can now confirm that the Corner Braking Control (CBC) is disabled on my 1M when I turn off fully the traction control.

Mike Benvo (bpmsport.com) coded the DSC ecm on my car so it operates like the E9x M3 so all traction control except the ABS is turned off when you hold the button down. In other words, the CBC is switchable.

Makes an enormous difference as I can now rotate the car using the brakes.

I'm glad this thread got bumped because I think I've been experiencing this phenomenon as well; it wasn't until I reread this thread that it started to make sense.

I'll be coming down a 120 mph straight with an upcoming sweeping left hander. In order to avoid apexing too early I drift over to the right across the blend line where pit road exits into this turn. This is about where the braking zone is and what I've noticed is that the rear end gets really squirrelly when I do this (drift towards the right, threshold brake, turn in...)

I run with MDM on the track and so I wonder if said coding can be done with MDM rather than when DSC is off? Or is disabling CBC in MDM a complete recipe for disaster (if it's even feasible.)

I can now confirm that the Corner Braking Control (CBC) is disabled on my 1M when I turn off fully the traction control.

Mike Benvo (bpmsport.com) coded the DSC ecm on my car so it operates like the E9x M3 so all traction control except the ABS is turned off when you hold the button down. In other words, the CBC is switchable.

Makes an enormous difference as I can now rotate the car using the brakes.

I'm extremely pleased

Neil

Does the software turn off both ABS and CBC or just CBC? Are ABS and CBC linked such that CBC can't be turned off without turning off ABS?

I can now confirm that the Corner Braking Control (CBC) is disabled on my 1M when I turn off fully the traction control.

Mike Benvo (bpmsport.com) coded the DSC ecm on my car so it operates like the E9x M3 so all traction control except the ABS is turned off when you hold the button down. In other words, the CBC is switchable.

Makes an enormous difference as I can now rotate the car using the brakes.

I'm extremely pleased

Neil

Congrats.

Have you tested or gotten confirmation that the CBC is still working as part of the default and/or MDM DSC setting?

Quote:

Originally Posted by Nugget

Can the ABS threshold be adjusted as well?

Once I get the 1MDSC module read sorted, by means of the .TRC file, we can start to 'decode' the meaning & impact of its parameters. I do expect the ABS feature to have parameters that can be changed. But how would one evaluate whether a certain change is a better tradeoff on the road? Not many would be willing (or able in safe environment) to try such a changed settings on their own car. TBC

Have you tested or gotten confirmation that the CBC is still working as part of the default and/or MDM DSC setting?

Didn't realize there was any traction control setting other than fully off

No, I haven't "played" with the traction control either fully on or in the intermediate MDM setting. However, I imagine that the CBC will be enabled in those two settings since Mike Benvo only altered the code for the system when it was fully turned off.

Neil

P.S. Just had a bit of correspondence with Mike and, for the moment, he's only now dealing with existing and previous customers so he can clear a backlog of work. If you really need to contact him, let me know offline and I'll get word to him.

What are the chances of a dealer detecting the DSC ECM program changes which may cause a warranty issue with them?
Are the DSC ECM programing changes that were made independent of any ECU programing being used?